Process for constructing intake pipe

ABSTRACT

With a method for constructing a water intake pipe, a vertical shaft 10 is constructed, and a shield tunnel 12 is constructed by causing a shield driving machine to advance from the vertical shaft 10 toward a seashore by breaking the wall of the vertical shaft 10. The tunnel 12 becomes a water intake pipe after the tunnel is constructed, and is built by annularly assembling segments 14 one after another at the rear side of the shield driving machine in line with the advancement thereof. Two types of segments 14, RC segments 18 and ductile segments 20, are used. The segments 20 are provided with water intake pores clogged by clogging members. After the tunnel 12 is constructed, workmen enter the shield tunnel 12 with compressed air supplied thereinto, and remove the clogging members of the ductile segments 20. After the clogging members are removed, sea water is gradually taken into the tunnel 12 through the water intake pores 20c while lowering the compressed air pressure so that sea water does not rush into the tunnel 12.

TECHNICAL FILED

The present invention relates to a method for constructing a waterintake pipe, and in particular a method for constructing a water intakepipe which is used to introduce a great amount of sea water into a seawater treatment plant such as a plant for turning sea water into freshwater, and a power generation plant such as a nuclear power generationplant.

BACKGROUND OF THE ART

A plant for turning sea water into fresh water was constructed in thevicinity of a seashore in order to obtain drinking water on an islandand a desert region where there is only a small amount of precipitation.Furthermore, sea water is, for example, prime water for a plant makingsalt. In this type of sea water treatment plant, it is necessary tointroduce a great amount of sea water into equipment for turning seawater into fresh water.

Furthermore, in a nuclear power generation plant, a great amount ofcooling water is required. Therefore, in this type of power generationplant constructed in a place adjacent to a seashore, a great amount ofsea water is required.

Therefore, conventionally, in such a sea water treatment plant and apower generation plant, sea water was taken in by a water intakestructure shown in FIG. 7.

In the water intake structure illustrated in the same drawing, a waterreservoir 1 is installed in the vicinity of a seashore, a watercollecting portion 2 is installed on the sea bottom, and a waterconveyance pipe 3 is used to connect the water reservoir 1 to the watercollecting portion 2, wherein sea water taken into the water reservoir 1is pumped up by a pump 4 and is distributed to various kinds offacilities.

A number of water intake pipes 4 protruding toward both sides of thewater conveyance pipe 3 are provided at the water collecting portion 2.A number of through holes are provided on the respective water intakepipes 4, and a synthetic resin net or unwoven cloth is wound on theouter circumference thereof in order to prevent earth and sand frominvading.

In such a water intake structure, usually, a water conveyance pipe 3 isburied by a driving method or a dig-sink method.

However, in such a conventional burying method of a water conveyancepipe 3, there existed the following shortcomings and problems in thetechnical aspects as described below.

That is, when burying a water conveyance pipe 3 by a driving method or adig-sink method, many limitations in working exist, resulting from thesurrounding vicinity of the place directly above the burying position ofthe water conveyance pipe 3 being exclusively occupied.

For example, in work carried out by the driving method in the sea, sincesea water is to be shut out, it becomes necessary to guarantee fisheryrights, and causes a hindrance in sea transportation.

Furthermore, when driving into the sea bottom, there is a fear that thesea will be polluted.

The invention was developed in view of such shortcomings and problemsinherent to the conventional art, and it is therefore an object of theinvention to provide a method for constructing a water intake pipe,which is able to construct a water intake pipe without exclusivelyoccupying the surrounding directly above the work site during theconstruction.

Furthermore, it is another object of the invention to provide a methodfor constructing a water intake pipe, which does not adversely influencethe surrounding environments of the work site during the construction.

DISCLOSURE OF THE INVENTION

In the invention, in a method for constructing a water intake pipe whichintroduces sea water to a sea water treatment plant such as a plant forturning sea water into fresh water and a power generation plant, avertical shaft which becomes a water reservoir after the construction iscompleted, is constructed in the vicinity of a seashore, and a shieldtunnel for a water intake pipe is constructed from the vertical shaft tothe seashore, and after the abovementioned shield tunnel is constructed,water intake pores for intake of sea water, which are provided atsegments of the abovementioned shield tunnel, are caused to communicatewith the outside.

According to the method for constructing a water intake pipe, which isthus constructed, the shield tunnel which becomes a water intake pipe,can be constructed from the vertical shaft without exclusively occupyingthe places directly above the tunnel.

It is possible to radially form a plurality of the abovementioned shieldtunnels from the abovementioned vertical shaft to a seashore.

The construction is preferable in a case where a great amount of seawater is taken in.

The abovementioned shield tunnel may be formed so that after it is onceformed from the abovementioned vertical shaft to a seashore, it returnsto the abovementioned vertical shaft after making a U-turn on the seabottom.

According to the construction, a shield driving machine which is used toform a shield tunnel can be easily collected and re-used.

The abovementioned water intake pores are provided in advance on theabovementioned segments and are closed with clogging members during theconstruction of the abovementioned shield tunnel. After thecorresponding shield tunnel is constructed, the abovementioned cloggingmembers are removed so that the water intake pores are caused to have asea water intake feature.

According to the construction, it is possible to smoothly form a shieldtunnel without any hindrance.

The clogging members can be removed by introducing compressed air intothe abovementioned shield tunnel while preventing sea water frominvading. Furthermore, the clogging members can be removed byintroducing sea water or fresh water into the shield tunnel.

The abovementioned segments consist of ductile segments which are ableto take in sea water through porous concrete portions by removing theabovementioned clogging members, and the ductile segments may be usedover the entire length of the shield tunnel.

The segments may be composed of RC segments made of steel reinforcedconcrete having almost no water permeability and ductile segments whichare able to take in sea water through porous concrete portions byremoving the abovementioned clogging members.

The RC segments may be provided at the vertical shaft side and the tipend side of the abovementioned shield tunnel.

After the abovementioned RC segments are cylindrically assembled, theymay be constructed so that a covering and lining layer and arust-preventive lining layer are formed on their interior side.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view of the process which is first carried outin a method for constructing a water intake pipe according to theinvention,

FIG. 2 is an explanatory view of the process which is performed justafter the first process in FIG. 1,

FIG. 3 is an explanatory view of a process which is performed after theprocess shown in FIG. 2,

FIG. 4 is an explanatory view of a process which is performed after theprocess shown in FIG. 3,

FIG. 5A is a perspective view showing, in an assembled state, oneexample of segments used for a method for constructing a water intakepipe according to the invention,

FIG. 5B is a cross-sectional side view of the intake pipe shown in FIG.5A.

FIG. 6 is an explanatory view showing another preferred embodiment of amethod for constructing a water intake pipe according to the invention,and

FIGS. 7A-B are explanatory views showing examples of conventional waterintake structure.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a detailed description is given of preferred embodiments ofthe invention with reference to the accompanying drawings. FIG. 1through FIG. 4 show one preferred embodiment of a method forconstructing a water intake pipe according to the invention.

With the constructing method illustrated in these drawings, first, asshown in FIG. 1, a vertical shaft 10 is constructed under the ground inthe vicinity of a seashore where a sea water treatment plant (notillustrated) such as a plant for turning sea water into fresh waterexists.

The vertical shaft 10 is constructed to an appointed depth, with itslower end closed, by using various types of soil-stopping wall methodand caisson method, which are already known. After the construction, thevertical shaft 10 is used as a reservoir of taken-in sea water.

After the vertical shaft 10 is constructed, a shield driving machine(not illustrated) is installed on the bottom and is advanced toward theseashore, breaking the wall of the vertical shaft 10, wherein a shieldtunnel 12 is shown by dashed lines in FIG. 1 is constructed.

The shield tunnel 12 becomes a water intake pipe after the constructionis completed, and is constructed by cylindrically assembling segmentsone after another at the rear side of the shield driving machine in linewith the driving of the shield driving machine as in construction of anordinary shield tunnel.

The shield tunnel 12 according to the preferred embodiment is caused tolinearly extend from the vertical shaft 10 toward a seashore, and thetip end thereof reaches an appointed depth below the sea bottom and ispositioned below the sea bottom.

Furthermore, not only may the single shield tunnel 12 may be providedfrom the vertical shaft 10 toward the seashore side, but also aplurality of shield tunnels may be radially provided from the verticalshaft 10 toward the seashore side.

After the construction such a shield tunnel 12 is completed, the shielddriving machine is left over at the tip end position of the shieldtunnel 12 as it is, and a tip end bulkhead 16 is secured at the tip endof the shield tunnel 12.

Furthermore, as segments of the shield tunnel 12 of the preferredembodiment, two types of segments are used, one of which issteel-reinforced concrete type RC segments 18 having almost no waterpermeability, and the other of which is cast iron type ductile segments20.

The RC segments 18 are used at the vertical shaft 10 side and the tipend side of the shield tunnel 12, and the ductile segments 20 are usedbetween these portions.

The RC segments 18 are those used in an ordinary shield constructionmethod, and are such that a cylindrical body having an appointed lengthis circumferentially divided into a plurality of sections, thesesections adjacent to each other in the circumferential and lengthwisedirections are connected to each other by bolts to be assembled so thatthey are cylindrical, and after a secondary covering concrete layer isformed on the inner circumferential surface of the assembled segments18, for example, an epoxy resin lining layer is formed to preventcorrosion on the further inner circumferential surface thereof.

One example of the ductile segments 20 employed for a shield tunnel 12according to the invention is illustrated in FIG. 5. The ductilesegments 20 illustrated in the same drawing are those in which acylindrical body having an appointed length is cylindrically dividedinto a plurality of sections as in the RC segments 18, and are such thatthe sections adjacent to each other in the circumferential andlengthwise directions are connected to each other, and they areassembled to be annular.

A ductile segment 20 is provided with a segment body 20a, porousconcrete portion 20b, water intake pores 20c, and clogging member 20d.The segment body 20a is constructed of cast iron plate or steel plateand is provided with a pair of connection flanges 200a at both ends inthe lengthwise direction, wherein two recessed portions 201a concaveinwardly are formed on the outer circumferential surface between theflanges 200a.

The porous concrete portion 20b is a porous body having waterpermeability and is poured and solidified in the recessed portion 201a.The water intake pores 20c are formed and caused to penetrate the flatbottoms of two continuous recessed portions 201a.

The clogging members 20d are detachably screwed onto the water intakepores 20c, whereby the clogging members 20d clog the water intake pores20c, and if the clogging members 20d are removed, the water intake pores20c are caused to communicate with the outside via the porous concreteportions 20b, thereby enabling water intake of sea water.

Since, at the ductile segments 20 illustrated in FIG. 5, porous concreteportions 20b are provided on the entire circumferential surface, it ispossible to collect sea water from the entirety of the portions, whereinthe water collection amount is further increased by increasing the watercollection range, and at the same time the velocity toward the waterintake pores 20c is made slower at the surface side, wherein it isadvantageous in that clogging scarcely occurs.

After the construction of the shield tunnel 12 is completed, as shown inFIG. 3, a bulkhead 20 is installed at the beginning side of the shieldtunnel 12, and compressed air is supplied into the shield tunnel 12,workmen enter the shield tunnel 12 and remove the clogging members 20dof the ductile segments 20.

In this case, since compressed air is provided in the shield tunnel 12,sea water is prevented from flowing into the tunnel through water intakepores 20c even though the clogging members 20d are removed, and sincethe compressed air introduced into the tunnel 12 leaks out while passingthrough the water intake pores 20c and porous concrete portions 20b, itis possible to prevent these portions from being clogged.

As all the clogging members 20d of the ductile segments 20 are removed,the compressed air pressure is gradually lowered so that sea water doesnot rush into the shield tunnel 12, wherein sea water is gradually takeninto the tunnel 12 through the water intake pores 20c.

At the same time, sea water is taken into the vertical shaft 10 whichwill become a sea water reservoir. After the water level in the verticalshaft 10 becomes identical to the sea level, the bulkhead 20 at thestarting side of the tunnel 12 is opened (See FIG. 4).

After such operations are completed, the construction of a water intakepipe composed of a shield tunnel is finished, a pump 24 is installed inthe vertical shaft 10, wherein it is possible to send sea water to atreatment facility side.

Thus, according to the method for constructing a water intake pipe, ashield tunnel 12 which becomes a water intake pipe can be constructedfrom the vertical shaft 10 without exclusively occupying a placedirectly above the shield tunnel. Therefore, no problem occurs withrespect to a hindrance in sea transportation, fishery rights, and oceanpollution, etc.

In the preferred embodiment, water intake pores 20c are provided inadvance in the segments 20 and are clogged by clogging members 20dduring the construction of a shield tunnel 12. After the correspondingshield tunnel 12 is completed, the clogging members 20d are removed tocause the shield tunnel 12 to communicate with the outside, wherein asea water intake function is given to the water intake pores 20c.Therefore, it is possible to smoothly construct the shield tunnel 12without any obstacle.

Furthermore, with the preferred embodiment, since porous concreteportions 20b are provided on the upper parts of the water intake pores20c, the porous concrete portions 20b functions as a filter, and it ispossible to prevent foreign substances such as sand and other matterfrom invading.

Furthermore, the clogging members 20d are removed while preventing seawater from invading by supplying compressed air into the shield tunnel12, and the introduced compressed air leaks out to prevent the waterintake pores 20c and porous concrete portions 20b from being clogged.

Still furthermore, introduction of compressed air when removing theclogging members 20c described in the abovementioned preferredembodiment is not limited to this method. For example, the cloggingmembers can be removed by diving operations with the water level in thevertical shaft 10 kept identical to the sea level by introducing seawater into the shield tunnel.

Furthermore, in the preferred embodiment, the entire shield tunnel 12 iscomposed of ductile segments 20 constructed above, and clogging members20c are removed at only the necessary sections, wherein a part of theshield tunnel 12 can be given a water intake function.

FIG. 6 shows another preferred embodiment of the invention, whereinparts which are equivalent to or identical to those in theabovementioned preferred embodiment are given the same referencenumbers, and the description thereof is omitted. Only the featuresthereof are described below.

In the preferred embodiment shown in FIG. 6, a shield tunnel whichbecomes a water intake pipe is composed of a first shield tunnel 12a anda second shield tunnel 12b. After the respective shield tunnels 12a and12b are formed from the vertical shaft 10 toward the seashore, they areformed so that they make a U-turn below the sea bottom and return to thevertical shaft 10 again.

When constructing such shield tunnels 12a and 12b, the first shieldtunnel 12a is formed, and a shield driving machine which has returned tothe vertical shaft 10 is subjected to a change of direction in thevertical shaft 10. Subsequently, the shield driving machine isre-started to form the second shield tunnel 12b, wherein the shielddriving machine which has returned is removed from the vertical shaft10.

The shield tunnels 12a and 12b are provided with ductile segments 20 atappointed sections thereof, and clogging members 20d are removed afterthe tunnels 12a and 12b are constructed, as in the abovementionedpreferred embodiment, and the water intake pores 20c are opened and aregiven a sea water intake function.

Furthermore, RC segments 18 illustrated in FIG. 6 may be used in onlythe vicinity of the vertical shaft 10, and sections other than thevicinity thereof may be constructed of ductile segments 20.

According to the method for constructing a water intake pipe thusconstructed, it is possible to construct a plurality of water intakepipes by using a single shield driving machine in addition to theactions and effects of the abovementioned preferred embodiment, andsimultaneously, it will become possible to collect and re-utilize ashield driving machine which forms the shield tunnels 12a and 12b.

If the constructing method according to the invention is adapted intopractice, for example, the treated remaining water containing high saltconcentration and warmed remaining water utilized for power generationmay be discharged and drained to the sea side through a shield tunnel.

INDUSTRIAL APPLICABILITY

As described above, a method for constructing a water intake pipeaccording to the invention is very effective in the construction ofwater intake pipes for introducing a great amount of sea water into asea water treatment facility such as a plant for turning sea water intofresh water and/or a power generation plant such as a nuclear powergeneration plant.

What is claimed is:
 1. A method for constructing a water intake pipe forintroducing seawater into a seawater treatment facility, comprising thesteps of:constructing a vertical shaft underground, which becomes areservoir, in land near a seashore; constructing a shield tunnel havingintake pores for a water intake pipe from pipe segments from thevertical shaft toward the seashore side wherein all construction isconducted underground and under a portion of sea bottom that is porousto seawater such that the entire, completed shield tunnel is undergroundand under said sea bottom; and opening said seawater intake poresprovided in said segments of said shield tunnel after said shield tunnelis constructed to allow seawater to flow through said shield tunnel andinto said shaft.
 2. A method for constructing a water intake pipe as setforth in claim 1, further comprising the step of radially constructing aplurality of shield tunnels from said vertical shaft toward the seashoreside.
 3. A method for constructing a water intake pipe as set forth inclaim 1, further comprising the step of constructing said shield tunnelso that, after it is formed to an appointed length from said verticalshaft toward the seashore, said shield tunnel makes a U-turn below thesea bottom and returns to said vertical shaft.
 4. A method forconstructing a water intake pipe as set forth in claim 1, furthercomprising the step of forming said water intake pores in said segmentsbefore said construction of said shield tunnel and using cloggingmembers to clog said pores during the construction of said shieldtunnel, wherein said pores function to conduct seawater upon removal ofsaid clogging members after said shield tunnel is constructed.
 5. Amethod for constructing a water intake pipe as set forth in claim 4,further comprising the step of introducing compressed air into saidshield tunnel before said clogging members are removed to prevent seawater from entering said shield tunnel until after all clogging membersare removed.
 6. A method for constructing a water intake pipe as setforth in claim 4, further comprising the step of removing said cloggingmembers with sea water or fresh water introduced in said shield tunnel.7. A method of constructing a water intake pipe as set forth in claim 4,further comprising the step of providing said segments with ductilematerial which is able to take in seawater through porous concretesections upon removal of said clogging members, and the ductile materialis used over the entire length of said shield tunnel.
 8. A method forconstructing a water intake pipe as set forth in claim 4, furthercomprising the step of providing said segments with steel-reinforcedconcrete made from RC segments having almost no water permeability, andductile material which is able to take in seawater through porousconcrete sections when said clogging members are removed.
 9. A methodfor constructing a water intake pipe as set forth in claim 8, furthercomprising the step of using said RC segments at the vertical shaft sideand a tip end side of said shield tunnel.
 10. A method for constructinga water intake pipe as set forth in claim 9, further comprising the stepof providing said RC segments with a cylindrical shape, and a coveringconcrete layer and a corrosion-preventing lining layer on an innercircumferential side thereof.